GREEK SCIENCE IN EARLY ATTIC PERIOD 



Anaxagoras and Diogenes (Apolloniates) , who say that 

 all animals respire, have also endeavored to explain 

 how fishes, and all those animals that have a hard, 

 rough shell, such as oysters, mussels, etc., respire. 

 And Anaxagoras, indeed, says that fishes, when they 

 emit water through their gills, attract air from the 

 mouth to the vacuum in the viscera from the water 

 which surrounds the mouth ; as if air was inherent in 

 the water." 2 



It should be recalled that of the three philosophers 

 thus mentioned as contending that all animals re- 

 spire, Anaxagoras was the elder; he, therefore, was 

 presumably the originator of the idea. It will be 

 observed, too, that Anaxagoras alone is held respon- 

 sible for the idea that fishes respire air through their 

 gills, "attracting" it from the water. This certainly 

 was one of the shrewdest physiological guesses of 

 any age, if it be regarded as a mere guess. With 

 greater justice we might refer to it as a profound 

 deduction from the principle of the uniformity of 

 nature. 



In making such a deduction, Anaxagoras was far in 

 advance of his time as illustrated by the fact that 

 Aristotle makes the citation we have just quoted 

 merely to add that "such things are impossible," and 

 to refute these "impossible" ideas by means of meta- 

 physical reasonings that seemed demonstrative not 

 merely to himself, but to many generations of his fol- 

 lowers. 



We are told that Anaxagoras alleged that all animals 

 were originally generated out of moisture, heat, and 

 earth particles. Just what opinion he held concerning 



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